1. Field of the Invention
This invention relates to a data recording apparatus for erasing data recorded on a recording medium then recording new data on the portion thus erased, and more particularly, to an optical magnetic disc apparatus for erasing data recorded on an optical magnetic disc and then recording new data on the portion thus erased.
2. Description of the Related Art
Conventionally, when accessing an optical magnetic disc, an of optical magnetic disc apparatus monitors for abnormalities such as a tracking error and retries write operations as needed.
When a host computer issues a write command, an optical magnetic disc apparatus erases the region for recording data, and then sequentially thermal magnetic records the data outputted from the host computer on a portion where the previous data has been erased.
At that time, the optical magnetic disc apparatus monitors a signal, such as tracking error signal, focus error signal, etc., to detect whether or not there is any abnormality in erasing processing or recording processing. When any abnormality is detected, the optical magnetic disc apparatus retries the erase or record operation.
Therefore, the optical magnetic disc apparatus is capable of recording and reproducing data without losing valuable data.
In a case where the optical magnetic disc apparatus retries writing data in the above manner, an abnormality may occur at only a small last part of a region to be erased, although the erasure has been normally performed to that point. In this case, it is wasteful to repeat the erasing operation from the beginning.
If such wasted time can be reduced the access time to the optical magnetic disc apparatus becomes shorter, thereby improving the usability of the optical magnetic disc apparatus.
However, when an abnormality is detected, the conventional optical magnetic disc apparatus interrupts a system control circuit to suspend the current processing, because the abnormal processing has the highest priority level. Therefore, detection of the abnormality unavoidably results in a time delay.
In addition, the time delay varies corresponding to the operation being executed at that time, such as during erasing, during succeeding from the erasing operation to the recording operation, etc., so that a conventional optical magnetic disc apparatus cannot precisely determine the processing time point when an abnormality has occurred.
Therefore, in the conventional optical magnetic disc apparatus, the problem is that it unavoidably wastes time repeating retries of write processing.